purple (usually) was ditto. Like carbon paper on steroids. you typed on a master and the upwards facing "carbon paper"* put a thick amount of ink on the other side of the sheet you typed on. Put that on a rotating drum, picking up the spirit (alcohol) and it would transfer a little bit to the sheet of paper then smooshed (technical term) against it. One master was good for maybe 100 copies. you might push to 200 but they would be hard to read and you had to set the machine to use less fluid. Best for under 50, like one class in school. One could find masters in other colors, though they were rare, I never saw them used except by math teachers to copy graphs with multiple colors. Or maybe just for a title like to get attention. You would create the document in the main color, then go back and use a new bottom to add the other colors. you could print a few, save the master, print a few more, etc, with no problems. mimeograph machines, that we called stencils, were something feeling like wax paper, you removed the ribbon from your typewriter and typed onto the master. I just learned that I/we mistakenly called ditto machines mimeograph. place the master on a drum with an ink feed and smoosh it against the target sheets, the ink would go through where your typewriter removed the waxy coating. Typically after 500-1000 copies the master would start deteriorating, like the white area inside an "o" or "R" would come off making a larger black spot. If you only made a few, you might be able to remove the master from the drum, save it against something that would get very inky and used it a second time. ---------------------- *carbon paper (I wonder if I have to explain this?): like tissue paper with a thin coating of dry ink on one side. Place, ink side down, between two sheets of plain paper, and whatever you write (with a pen) or type will make a second copy on the second sheet of paper. Computers could print on at least "6-up" with the original getting ink from the computer printer's ribbon and 5 more copies from carbon paper. separate, offline machines separated the carbons from the copies on a continuous basis, one box at a time. then there was NCR "no carbon required". two sheets of paper, the first had a chemical on the bottom that when smooshed onto the chemical on the top of the second sheet brought out an ink-like color. I still use checkbooks like this. I remove the check before I sign it so there will not be a copy of my signature, not even a physical impression. the copier i referenced before was called photostat, and I had forgotten the copy was a negative.under it Carey
On 04/21/2026 9:38 AM CDT D. Hugh Redelmeier via Talk <talk@lists.gtalug.org> wrote:
From: Sam K via Talk <talk@lists.gtalug.org>
D. Hugh Redelmeier wrote:
I remember when Xeroxing was new and expensive. In 1967 or 1968 I used a copier at the old TPL Central Reference Library at College and St. George. I paid something like $0.25 a page! Real money then. It was some chemically thing, not Xerox. (I now have that book from which I copied a paper. You can too <https://archive.org/details/programmingsyste0000saul>)
Hugh, was this copy purple in colour and smelled of vinegar? or was it nail polish?
It was a long time ago. My memory of it is fuzzy. The topic of the paper was an example compiler written in LISP, including the code. This intrigued my Grade 12 imagination. I aimed to write an Algol 60 compiler for the IBM 1710 that was across St. George, in the Galbraith building (I was using that computer, eventually with tacit approval). GTALUG meatings were in that building for many years.
Purple makes me think of mimeograph and methyl alcohol, but that required a "stencil", so that cannot be what you are refering to.
The copy was grey with perhaps a bit of brown, if I remember correctly.
Given the two choices of smell you listed, I'm inclined to pick vinegar. ------------------